A monopoly is defined by utilizing aggression to keep new entrepreneurs from providing a service in the market.

Since bitcoin miners are anonymous, and since they only need compute power to provide a service, bitcoin mining is hardcore anti-monopoly, or in other words, a radical free market.

Whenever there is no opportunity for monopoly, new entrepreneurs can always sweep in to provide the service, even if there's only a tiny bit of profit possible. Thus the price for the good (hash price) will tend towards the marginal cost of production, so that there's very little profit opportunities, meaning if you're not incredibly efficient and provide the hash at very low cost, you are likely unprofitable and just burning your money.